Billy,
My Dietz were only three wire (red low beam, green high beam, black ground) so yours must have a marker lamp internal? My guess is that they will be red low, green high, blue ground and yellow marker. You likely know this, but you can check continuity/resistance to verify the colors - clamp one lead on your blue wire, and you should see continuity to the red with some resistance for the low beam filament, continuity to the green with a higher resistance for the high beam, and then continuity with a much lower resistance for the marker. If that checks than a quick check with a hot wire from your battery to the yellow, red and then green will verify the colors.